1. Field of the Invention
The present invention relates generally to the field of emergency signalling devices, and more specifically to a combination emergency signalling apparatus for use on boats, including an optically reflective sheet for spreading over the top of a bimini top frame or a cabin, having embossed upon its upper surface a distress message, such as SOS, in nonreflective letters, a strobe light mounted at the center of the sheet and connected to a power source and to a timer assembly to flash a distress message in Morse code, and at least one upwardly directed light also connected to the power source and to a timer to flash a Morse code distress message, which is preferably connected to an optical sensor switch assembly to turn the light on at night, and optionally connected to a photovoltaic cell for recharging the power source by day.
2. Description of the Prior Art
There have long been emergency signalling devices for use on boats and ships. The history of maritime distress signals would necessarily begin contemporaneously with man's first journeys onto a bodies of water aboard buoyant objects. The first ships are believed to have been floating logs that carried prehistoric man across lakes and rivers. During the Stone Age, which began about 1,000,000 B.C., man learned to hollow out the logs using stone axes and fire. Distress signals in these early days were probably limited to frantic hand gestures and cries for help. By 3000 B.C. the island of Crete maintained a large fleet of open vessels propelled by oars known as galleys, to trade with nations bordering on the Mediterranean Sea. During this period, the Egyptians were navigating the Nile River in boats made of tied bundles of reeds. Within the next millennium, the Egyptians were building ships out of planks imported from Phoenicia. By 1000 B.C., the Phoenicians themselves dominated Mediterranean trade, followed by the Greeks and Romans. After the Crusades, ships became wider and deeper and more sails were added. The developments eventually led to the caravel design, then to the galleon in the 1500's and the clipper ship in the 1800's. Steam was successfully harnessed to propel ships by James Watt in the 1700's, and was eventually replaced with the internal combustion engine.
During the evolution of seafaring, there was a parallel evolution in the nature and technology of marine distress signals. Man learned to shout through primitive megaphones, to flash lights and, with the advent of steam power, to sound the fog horn, the whistle and the siren. Various flags were flown or waved, such as in Semaphore signals, and flares and other fireworks were launched. The twentieth century brought the wide use of radio to marine travel.
These methods have all failed at various times. The Titanic launched flares and radioed for help. Yet the nearest ship, the Californian, is believed to have had its wireless receiver shut off and to have initially ignored the flares. Techniques for protecting ships have improved since then, so that today help can be quickly and reliably summoned.
Developing distress signalling means for small boats has, however, presented unique problems. The signalling apparatus must be relatively compact and inexpensive. A problem with the flare is that it only generates a signal for a few seconds. The siren can operate continuously, but is limited by the relatively short range of the sound it generates. Search pilots, for example, would not likely hear a siren. As for radio, most small boats are not equipped with transmitters, and humid, salty air limits reliability.
Other devices have been developed as well, but present their own disadvantages. Todd, U.S. Pat. No. 4,987,848, issued on Jan. 29, 1991, discloses a radar reflecting signal flag. The flag is made of durable, synthetic threads, and has the outward appearance of a conventional flag or pennant flown on boats. The synthetic threads are, however, impregnated with metallic particles to reflect radar waves and indicate the location of the boat. A problem with Todd is that the flag is intended to be flown at all times, so that its deployment does not alert anyone to an emergency. Another problem is that radar detection is only moderately reliable at such a low elevation. Still another problem is that, search planes generally do not have radars responsive to this type of signal, and ships, which do, are too slow; therefore, the flag would rarely be helpful.
Rowland, U.S. Pat. No. 4,813,025, issued on Mar. 14, 1989, teaches a nautical signalling device using radio and ultrasonic waves. Interrogation signals are transmitted to the boat through both air and water, and automatically trigger the generation of a response signal from the unit on the boat. The elapsed time from transmission to reception and the direction of response signals are recorded and used to locate the missing boat. A problem with Rowland is that the device is dependant upon complex and sophisticated electronics to an extent that it would likely be prone to failure for a myriad of reasons. The salt environment would certainly aggravate this problem. The complexity may also make Rowland expensive beyond the means of the typical small boat owner.
Kolesar, U.S. Pat. No. 4,809,638, issued on Mar. 7, 1989, reveals a liquid film material carried by a floating survivor in a packet for deployment on the surface of the water around him. This film material contains an ingredient for reducing water surface tension to eliminate capillary waves. A second ingredient reduces evaporation. The combined effect is supposed to reduce radar back-scatter in comparison with the surrounding water and make the slick both visible to the eye and to radar. A problem with Kolesar is that it is intended for use by a survivor floating in the water, and is not well suited for drawing attention to a boat in distress. The boat itself could block reflection from the slick, and the slick may appear from the air to be nothing more than discharge from the boat engines.
Bien, U.S. Pat. No. 4,053,233, issued on Oct. 11, 1977, teaches another type of signalling reflector. The invention is a small multifaceted object, having a retroreflector on each facet, and attached to a stem member for mounting on a boat, on a survivor's clothing, on his life raft or his life preserver. Each retroreflector is supposed to be able to reflect at 180 degrees a laser beam or other radiated signal. A problem with Bien is that, unless a nearby search vessel already knows the boat is in trouble and has its search signals activated, the boat's distress will go unnoticed. Bien also depends on the search vessel being equipped with the necessary signalling equipment.
McDonald, U.S. Pat. No. 3,952,694, issued on Apr. 27, 1976, discloses a marine signalling device in the form of a broad surfaced member connected to a boat or person, such as a length of plastic sheeting. The sheeting is formed of a buoyant material which is colored to contrast with the water, and is unfolded to float upon the surface of the water and trail from the stranded boat or person. A problem with McDonald is that its deployment could take large amounts critical time. Furthermore, the current could carry it back to wrap around the hull of the boat. And should it be mishandled, it may break loose and float away. Finally, it is only minimally effective at night.
Bearing in mind the foregoing, it is a principal object of the present invention to provide a marine signalling apparatus which can be rapidly deployed and reliably secured.
Another object of the present invention is to provide such an apparatus which is relatively inexpensive to make and easy to use.
A further object of the present invention is to provide such an apparatus which operates effectively during both day and night.
An additional object of the present invention is to provide such an apparatus which is not merely detectable but which also clearly communicates distress.